The present invention relates to a linear motion device.
A linear motion device is made known in DE 10 2007 043 391 A1. FIG. 1 of DE 10 2007 043 391 A1 shows a linear motion device 10 in the form of an electric cylinder. The linear motion device includes a tubular housing 30 that extends in a longitudinal direction 12 and is extruded out of aluminum. A ball screw spindle 11 is rotatably accommodated in the housing. The ball screw spindle is engaged in a threaded manner with a rotor 20 in the form of a recirculating ball nut, thereby enabling the rotor to move in the longitudinal direction via a rotation of the spindle. The rotor is fixedly connected to a tubular arm 23 that extends out of the housing on a longitudinal front side, thereby enabling it to be retracted and extended via a rotary motion of the spindle relative to the housing.
The disadvantage of this linear motion device is the complicated lubrication of the rotor in the form of a ball screw nut. For this purpose, a lubricant supply device in the form of a closeable opening is provided on the housing. To be lubricated, the rotor must be moved into a longitudinal position in which the aforementioned opening is located directly opposite a lubricant delivery bore in the rotor. In this position, lubricant may now be filled into the rotor via the lubricant delivery bore, using a grease gun. This lubricating procedure absolutely must be performed manually.